1. Field of the Invention
This invention relates generally to refining apparatus and, more specifically, to a refining apparatus for separating the heavier constituents from a mixture of materials.
2. Description of the Prior Art
In the past, achieving a separation of a mixture of materials into heavier and lighter portions has been a recurring problem in various fields. One such field has been the separation of precious minerals from their natural habitat.
Gold, a typical one of such minerals, has been the subject of such attempts at separation, or refining, from time immemorial. The traditional approach to the separation of free, or placer, gold has been to deposit the mixture of materials in a flow of water passing through a sluice, or riffle, box. When entrained in such a flow, the various constituents of the mixture of materials were fluidly suspended, thereby permitting any gold, or other heavy materials such as rubies, sapphires, diamonds, etc., to descend to the bottom of the sluice box. Typically, the sluice box was provided with a series of riffle boards coupled to the bottom of the sluice box at right angles to the direction of the flow of water. In this manner, the heavy materials descending to the bottom of the sluice box were trapped behind the respective riffle boards. The most serious limitation on such a water sluice was the requirement for water. As free gold is commonly found in arid areas, such a water sluice was either totally inoperable or, at best, useful during only a limited portion of the year when water was available.
In an attempt to overcome this problem, various dry washer devices have been developed. As described in a 1961 Arizona Bureau of Mines publication entitled Gold Placers and Placering in Arizona, typical dry washers utilized a cloth-bottomed, inclined separating tray, through which air was pulsed to separate the heavier components. As the air passing upward through the cloth also tended to fluidly suspend the gold, the relative efficiency of such devices was limited. A need existed for a dry washer which would permit the heavier components of a mixture of materials to be fall out of the fluid suspension caused by the upwardly moving air.